In September 2003, a National Academy of Sciences (NAS) Committee on Developing a Strategy to Reduce and Prevent Underage Drinking released a report requested by Congress stating that the societal cost of underage drinking in the United States is estimated to be $53 billion per year. The report notes, "The committee conducted its work within the current national policy establishing 21 as the minimum legal drinking age in every state." Despite the fact that the National Highway Traffic Safety Administration claims that the minimum legal drinking age laws save 900 lives a year, there is still considerable controversy over their effectiveness: 45 states have exceptions to their minor-in-possession laws and 5 states have legislation that would immediately lower their drinking age to 18 if Congress fails to extend the Uniform Drinking Age Act. In December 1999, New Zealand lowered its drinking age from 20 to 18, providing the best opportunity in the last quarter century to examine the affect of such an increase. The Pacific Institute for Research and Evaluation and the University of Otago in New Zealand are joining in an R21 application to conduct a secondary analysis of drinking age change. New Zealand has unusually complete national, crash, police, and hospital records with ICD9 codes that contain data on the affected age groups. In addition, the university has access to two national alcohol surveys before and after the law changed. Changes in three major domains--alcohol consumption and problems, traffic and nontraffic injuries, and highway crashes--will be analyzed to determine whether alcohol-related problems increased for the affected 18- and 19-year-old drivers in comparison to a 20- to 24-year-old comparison group.